Vasectomies are performed on millions of men worldwide annually. For example, approximately 500,000 vasectomies are performed each year in the United States alone. Of those men that receive vasectomies, approximately five percent of such men subsequently choose to have their vasectomies reversed. Vasectomies generally involve altering the human male anatomy such that sperm cells are unable to mix with seminal fluid.
In a human male, sperm cells are created in the testicles. The sperm cells migrate from the testicles to the epididymis, a long, coiled tube that connects the testicles to the vas deferens. At the time sperm cells enter the epididymis, they are unable to fertilize an egg without assistance. However, the sperm cells mature as they travel through the epididymis and exit the epididymis capable of fertilizing an egg. Mature sperm cells enter the vas deferens from the epididymis and flow through the vas deferens to the seminal vessel. There, the sperm can enter seminal fluid which can then enter a human female and fertilize an egg.
To prevent fertilization, or for any other reason, some men choose to have a vasectomy performed. To perform a vasectomy, a surgeon typically creates an opening in the scrotum using either a scalpel or some other suitable means, and exposes the vas deferens. The vas deferens is then cut or separated and the two resulting open portions of the vas deferens are sealed. For example, each side of the separated vas deferens may be sealed using sutures or cauterization.
The vas deferens is severed to prevent sperm exiting the epididymis from flowing through the vas deferens and ultimately becoming part of the seminal fluid. In this way, any seminal fluid exiting the human male will lack sperm. If seminal fluid does not contain sperm, fertilization cannot take place using traditional means. Therefore, vasectomies can be effective birth control procedures. However, some men wish to reverse a successful vasectomy and restore normal sperm flow.
Generally, two different types of surgeries, or repairs, exist to reverse vasectomies. Whichever surgery is used, the purpose of the surgery is to reestablish the flow of sperm cells from the testicle through the vas deferens. The first repair involves reconnecting the disconnected portions of the vas deferens created by the vasectomy. The second repair is more complicated than the first repair and requires the vas deferens to be reconnected directly to the epididymis instead of the other portion of the vas deferens created by the original vasectomy. Thus, a portion of the vas deferens is bypassed in the second repair.
The first repair is generally preferred because of the differences in size and composition between the vas deferens and the epididymis. The vas deferens is relatively tough and about 3 millimeters in diameter. In contrast, the epididymis is relatively fragile and roughly 0.3 millimeters in diameter. Thus, it is generally easier to surgically reconnect two different portions of the vas deferens than to connect the vas deferens to a portion of the epididymis.
Although the first repair is generally preferred, sometimes the second repair is required. For a variety of reasons, after a vasectomy is performed, obstructions can occur in either the epididymis or the vas deferens. For example, the sperm that are unable to migrate through the vas deferens can form an obstruction, or sperm plug, in either the epididymis or in the portion of the vas deferens still in fluid communication with the testicles. One indication that sperm have formed a speilii plug is the observation that vasal fluid has small clumps of solid material within the fluid.
The second repair, sometimes called epididymal bypass surgery, is much more expensive and complicated than the first repair. The second repair can last about an hour and can require an epidural or a general anesthetic. In contrast, the first repair can require only a local anesthetic and lasts a significantly shorter amount of time.
In addition to the greater complexity of the procedure, the second repair is generally less successful than the first repair. Published studies since the 1980's report sperm return in only 60% to 68% of patients and pregnancy rates in about 25% to 57% of patients. Both ranges are lower than the rates for the first repair. Therefore, if a nonsurgical solution could be found for those patients that had in the past required the second repair, patients could be saved the pain, expense and potential complications associated with the second repair.